Earth heat transfer loop apparatus

ABSTRACT

An earth loop heat transfer system which, in certain aspects, has a heat transfer loop extending down into the earth and having a first portion, a second portion, and a bottom portion at a first level in the earth, heat transfer fluid flowable down to the bottom portion and up therefrom and in the second portion to the earth surface, and valve apparatus in the heat transfer loop for controlling flow of heat transfer fluid; and, in one aspect, such a system combined with a rig useful in well operations for supplying heat transfer fluid for use on the rig, either from a loop or loops with portion(s) in water or portion(s) in earth, or both.

CROSS-REFERENCES TO RELATED APPLICATIONS

This is a division of U.S. application Ser. No. 11/132,512 filed May 19,2005 (U.S. Pat. No. 7,128,156; Oct. 31, 2006) which is a division ofSer. No. 10/459,331 filed Jun. 11, 2003 (U.S. Pat. No. 6,896,054; May24, 2005), a continuation-in-part of U.S. application Ser. No.10/047,944 filed Jan. 14, 2002 (U.S. Pat. No. 6,585,067; Jul. 1, 2003),a continuation-in-part of U.S. application Ser. No. 09/504,172 filedFeb. 15, 2000, (U.S. Pat. No. 6,267,172; Jul. 31, 2001) and U.S.application Ser. No. 09/620,954 filed Jul. 21, 2000 (U.S. Pat. No.6,338,381; Jan. 15, 2002)—all said applications and patents incorporatedfully herein for all purposes and from all of which the presentinvention claims priority under the Patent Laws.

BACKGROUND OF THE INVENTION

1. Field Of The Invention

The present invention, in at least certain embodiments, is directed toearth heat exchange systems for exchanging heat between an earth conduitand/or earth loop; in certain particular aspects, to such systems usedwith methods for introducing microorganisms (e.g. bacteria) into oilbearing formations to enhance oil recovery; and in other aspects to suchsystems used in geothermal power plants.

2. Description of Related Art

The prior art discloses a wide variety of earth heat exchange systems.Typically such systems include conduit, conduits, and/or a pipe loopwithin the earth, apparatus for circulating heat transfer fluidtherethrough and through other systems or apparatuses above the surface,and heat exchange apparatus for exchanging heat between the transferfluid and an item, apparatus, device or other thing. U.S. Pat. No.6,543,535 issued Apr. 8, 2003 discloses, among other things, processesfor stimulating microbial activity in a hydrocarbon-bearing earthformation to assist in the conversion of hydrocarbons to methane, whichprocesses include modifying the formation environment by modifying theformation temperature.

SUMMARY OF THE PRESENT INVENTION

The present invention, in certain aspects, discloses a wellbore methodincluding providing with a primary system a fluid with microorganisms,the primary system including introduction apparatus, with theintroduction apparatus introducing the fluid with microorganisms into anearth formation bearing hydrocarbons, the microorganisms forfacilitating removal of the hyrdrocarbons from the earth formationbearing hydrocarbons (e.g., oil), effecting heat exchange between thefluid with microorganisms and heat transfer fluid that has traversed anearth loop of an earth loop heat exchange system, the earth loop heatexchange system with an earth loop extending from an earth surface downinto the earth with the heat transfer fluid flowable through the earthloop and heat transfer apparatus for transferring heat between the fluidwith the microorganisms and the heat transfer fluid.

The present invention, in certain aspects, discloses processes forstimulating the activity of microbial consortia in a hydrocarbon-bearingincluding: analyzing one or more components of the formation todetermine characteristics of the formation environment; detecting thepresence of microbial consortia within the formation; determining one ormore characterizations of one or more microorganisms of the consortia;determining an ecological environment that promotes in situ microbialdegradation of hydrocarbons by at least one microorganism of theconsortia; and modifying the formation environment to stimulatemicrobial degradation of hydrocarbons, the modification of the formationincluding injecting into the formation an aqueous solution (or a heattransfer fluid) that modifies formation temperature, the aqueoussolution provided by or processed in heat transfer relation with anearth loop heat exchange system.

The present invention, in certain aspects, discloses geothermal powerplant systems operating on geothermal fluid (e.g., at low, intermediate,or high pressure) and including a source of geothermal steam derivedfrom said geothermal fluid; one or more turbo-generators, the or each ofthem including a steam turbine coupled to a generator; apparatus thatapply steam from the source to the turbine wherein expansion of thesteam takes place driving the generator and producing electricity, andproducing expanded steam; a condenser that condenses the expanded steam;the condenser including a steam heat exchanger that receives theexpanded steam; a fan or other cooler for cooling the expanded steam;and an earth loop heat exchange system with an earth loop extending froman earth surface down into the earth with heat transfer fluid flowablethrough the earth loop and heat transfer apparatus for transferring heatbetween part (e.g., any flow line, conduit, turbine, generator, heatexchanger, flash unit, etc. for heating or cooling of them) of thegeothermal power plant system and the heat transfer fluid.

The present invention, at least in certain preferred aspects, disclosesa system for heating or cooling a rig, apparatus thereon, a pipeline(above ground, under ground, and/or under water), pipe, wellbore or ariser, the system including an earth heat exchange conduit or loopwithin the earth and heat exchange apparatus for conveying heated (orcooled) transfer fluid circulating through the earth heat exchangeconduit or loop to the rig, pipe, wellbore, riser, or pipeline. The heatexchange apparatus may encompass a portion of an item's exterior and/orit may include heat exchange device(s) within the item or pipeline toheat or cool fluid flowing therein.

In certain embodiments according to the present invention the heatexchange apparatus is permanently or semi-permanently installed on apipe, rig, riser, or pipeline section. In other embodiments a movablejacket or module is used that is selectively interconnectible to one ofa series of earth heat exchange conduits or loops so that a selectedportion of the section can be heated or cooled. In another aspect amobile heat exchange apparatus is used within a pipe, riser, or apipeline that can be connected so that it is in fluid communication withan earth heat exchange system nearby. In certain embodiments one or moreflow rate control devices are used within a conduit or loop to controland/or maintain fluid flow rate through a portion thereof.

In one aspect an earth conduit or loop is provided that has a portionthereof that is insulated. In another aspect one or more valves and/orone or more flow rate control devices are used in an earth conduit orloop to control fluid flow rate therein and/or to selectively flow heattransfer fluid through a selected portion of a loop or conduit.

What follows are some of, but not all, the objects of this invention. Inaddition to the specific objects stated below for at least certainpreferred embodiments of the invention, other objects and purposes willbe readily apparent to one of skill in this art who has the benefit ofthis invention's teachings and disclosures. It is, therefore, an objectof at least certain preferred embodiments of the present invention toprovide:

New, useful, unique, efficient, nonobvious devices, systems, and methodsfor using microorganisms such as bacteria to enhance hydrocarbonrecovery from a well and employing an earth loop heat exchange systemfor this;

New, useful, unique, efficient, nonobvious devices, systems, and methodsfor geothermal power plants used with an earth loop heat exchangesystem;

New, useful, unique, efficient, nonobvious devices and methods fortransferring heat between a rig or pipeline and heat transfer fluidcirculating through an earth conduit or loop;

Such devices and methods wherein a heat exchange device is selectivelyemplaceable at a desired location and removably interconnectible withone, two, three, or more or a series of a plurality of earth conduitsand/or loops;

Such devices and methods with remotely controlled controllers, pumps,etc;

Such devices and methods with pumps, etc. powered with a solar powersystem and/or a wind power system;

Such devices and methods for a portion of a pipeline above ground and/orbelow ground;

Such devices and methods with a heat exchange device on the outside ofor within a pipeline;

Such devices and methods with a heat exchange device movable within apipeline;

Such devices and methods with a heat exchange device within a wellbore,the device in fluid communication with an earth conduit or loop;

Such devices and methods with an earth conduit or earth loop having aninsulated portion to enhance heat transfer efficiency; and

Such devices and methods with one or more pumps, valves, and/or flowcontrol devices in an earth conduit or loop, or in part thereof, or inan earth loop with one or more crossover portions.

Certain embodiments of this invention are not limited to any particularindividual feature disclosed here, but include combinations of themdistinguished from the prior art in their structures and functions.Features of the invention have been broadly described so that thedetailed descriptions that follow may be better understood, and in orderthat the contributions of this invention to the arts may be betterappreciated. There are, of course, additional aspects of the inventiondescribed below and which may be included in the subject matter of theclaims to this invention. Those skilled in the art who have the benefitof this invention, its teachings, and suggestions will appreciate thatthe conceptions of this disclosure may be used as a creative basis fordesigning other structures, methods and systems for carrying out andpracticing the present invention. The claims of this invention are to beread to include any legally equivalent devices or methods which do notdepart from the spirit and scope of the present invention.

The present invention recognizes and addresses the previously-mentionedproblems and long-felt needs and provides a solution to those problemsand a satisfactory meeting of those needs in its various possibleembodiments and equivalents thereof. To one skilled in this art who hasthe benefits of this invention's realizations, teachings, disclosures,and suggestions, other purposes and advantages will be appreciated fromthe following description of preferred embodiments, given for thepurpose of disclosure, when taken in conjunction with the accompanyingdrawings. The detail in these descriptions is not intended to thwartthis patent's object to claim this invention no matter how others maylater disguise it by variations in form or additions of furtherimprovements.

DESCRIPTION OF THE DRAWINGS

A more particular description of embodiments of the invention brieflysummarized above may be had by references to the embodiments which areshown in the drawings which form a part of this specification. Thesedrawings illustrate certain preferred embodiments and are not to be usedto improperly limit the scope of the invention which may have otherequally effective or legally equivalent embodiments.

FIG. 1 is a schematic view in cross-section of a system according to thepresent invention.

FIG. 2 is a schematic view in cross-section of a system according to thepresent invention.

FIG. 3 is a schematic view in cross-section of a system according to thepresent invention.

FIG. 4 is a schematic view in cross-section of a system according to thepresent invention.

FIG. 5 is a schematic view in cross-section of a system according to thepresent invention.

FIG. 6 is a schematic view in cross-section of a system according to thepresent invention.

FIG. 7 is a schematic view in cross-section of a system according to thepresent invention.

FIG. 8 is a schematic view in cross-section of a system according to thepresent invention.

FIG. 9A is a view in cross-section of a system according to the presentinvention.

FIG. 9B is a view in cross-section of a system according to the presentinvention.

FIG. 10 is a schematic view in cross-section of a system according tothe present invention.

FIG. 11 is a schematic view in cross-section of a system according tothe present invention.

FIG. 12 is a schematic view in cross-section of a system according tothe present invention.

FIG. 13 is a schematic view in cross-section of a system according tothe present invention.

FIG. 14 is a schematic view in cross-section of a system according tothe present invention.

FIG. 15 is a schematic view in cross-section of a system according tothe present invention.

FIG. 16 is a schematic view in cross-section of a system according tothe present invention.

FIG. 17A is a block diagram of a geothermal power plant according to thepresent invention for utilizing geothermal fluid produced from a well.

FIG. 17B is a block diagram of a geothermal power plant according to thepresent invention for utilizing geothermal fluid produced from a well.

FIG. 17C is a block diagram of a geothermal power plant according to thepresent invention for utilizing geothermal fluid produced from a well.

FIG. 18 is a schematic view in cross-section of a system according tothe present invention.

DESCRIPTION OF EMBODIMENTS PREFERRED AT THE TIME OF FILING FOR THISPATENT

Referring now to FIG. 1, a system 10 according to the present inventionincludes an earth heat loop 12 made of any suitable conduit or pipematerial through which a heat transfer fluid can be circulated. The loop12 extends down into the earth E to a desired depth, e.g., but notlimited to, a depth at which the temperature of the earth is between 60°F. and 80° F. Higher (and lower) temperatures can often be encounteredat various depths in the earth and any loop (or earth conduit) disclosedherein may extend to such depths as desired.

A pump 14 pumps the heat transfer fluid through the loop 12 and througha heat exchange apparatus, e.g. but not limited to, a conduit 16, aportion of which encompasses a portion of a pipeline 18 through whichfluid flows. Alternatively, or in addition to the pump 14, a pump 19beneath the earth's surface pumps fluid through the loop 12 and theconduit 16. The conduit 16 is in fluid communication with the loop 12 sothat heat transfer fluid is pumped through the loop 12 to the conduit12, and back through the loop 12 continuously.

In situations in which the temperature of the environment of thepipeline is relatively cold, e.g. but not limited to 32° F. or below, or0° F. or below, the heat transfer fluid is pumped through a loop 12 to asufficient depth and the loop is of sufficient length that the fluid iswarmed and then, by heat exchange, warms the portion of the pipeline 18and, hence, fluid within that portion of the pipeline. The conduit 16can be any desired length. Optionally, insulation 17 is provided aroundthe conduit 16 and/or the pump 14. Also, as described below, part of theloop under the earth's surface may be insulated. In situations in whichthe pipeline's environment is relatively hot, e.g., but not limited to100° F. or hotter, the heat transfer fluid at a cooler temperature, e.g.between about 70° F. to 80° F., can be used to cool, by heat exchange,the portion of the pipeline 18 encompassed by the conduit 16.

FIG. 2 illustrates a system 20 according to the present invention inwhich a pipeline 28 is buried in the earth E. An earth loop 22 has alower portion in fluid communication with an upper heat exchange portion26 that encompasses a part 23 of the pipeline 28. The part 23 of thepipeline 28, and hence fluid in that part of the pipeline, may be at onetemperature while heat transfer fluid with a pump 24 pumped through theloop 22 is of a different temperature. Thus, as with the system 10, bycirculating heat transfer fluid through the loop 22 and the conduit 26the part 23 of the pipeline can be cooled or heated, depending on thetemperature differential of the earth adjacent the loop 12 and adjacentthe part 23 of the pipeline, and depending on the temperature of fluidflowing through the pipeline. Alternatively, a portion of the conduit 26or loop 22 can extend above the earth surface and a pump can bepositioned there to circulate fluid through the loop and the conduit.Either a sufficient length of conduit 16 or 26 are used, or anappropriate heat exchange apparatus in fluid communication with theconduit is used, to effect a desired temperature change for a pipelineportion and/or fluid flowing through the pipeline portion.

FIG. 3 illustrates a system 30 for a pipeline 38 above the earth E thatincludes three earth loops 32 a, 32 b, 32 c which extend down into theearth E to a desired depth which is at a desired temperature. Associatedwith and in fluid communication with each earth loop is a heat exchangeapparatus, e.g., but not limited to conduits 36 a, 36 b, 36 c each ofwhich is in fluid communication with a corresponding earth loop. It iswithin the scope of this invention for the pipeline 38 to be buried inthe earth. It is within the scope of this invention to have any desirednumber of spaced-apart earth loops in proximity to and/or along thelength of the pipeline.

A cable 31 interconnects a control apparatus 33 a for a pump 34 a with acontrol function 35 that may be near the pipeline or located remotelywith respect to it. Another cable 35 a interconnects the controlapparatus 33 a with other control apparatuses 33 b and 33 c. The controlfunction can selectively activate or deactivate any, all, or anycombination of the pumps 34 a, 34 b, 34 c to selectively heat (or cool)portions of the pipeline 38 corresponding to the conduits 36 a, 36 b, 36c.

A sensor 39 a in communication with the control apparatus 33 a signalsthe temperature of the pipeline 38 to thermostat apparatus andassociated devices in the control apparatus 33 a to activate ordeactivate the pump 34 a at desired pre-set pipeline temperatures and/orvia the cable 31 temperature information is conveyed to the controlfunction 35 and subsequent activation or deactivation of the pump 34 ais accomplished (and, hence, corresponding heating or cooling of thepipeline and its contents via the conduit 36 a). Such a sensor (like thesensor 39 a) and related apparatus may be used with each of the pumps 34b and 34 c and their control apparatuses.

Sensor 39 b is connected to the control apparatus 33 b and operates in amanner similar to that of the sensor-39 a/controller-33 a combination;but the sensor 39 b is inside the pipeline 38. A sensor 39 b and relatedapparatus may be used with each of the pumps 34 a, 34 c and theircontrol apparatuses.

Alternatively (or in addition to the cable 31) signals and data may betransmitted to and from the system 30 using wireless communication andassociated transmitters and receivers at a control function (like thecontrol function 35) and in the control apparatuses 33 a, 33 b, 33 c,e.g. but not limited to, via one or more antennas 39.

A suitable enclosure and/or insulation material 37, shown enclosing theconduit 36 c and related apparatuses, may be used with the conduits 36a, 36 b and related apparatuses.

Power for the pumps and control apparatuses of the system 30 may beprovided via suitable cables or lines. Alternatively, or in addition tosuch power, a solar collector 41 with storage batteries 42 may be usedto provide power for the system 30 and/or a wind-driven power generatingsystem 43 with storage batteries 44 may be used. It is within the scopeof this invention to provide such power source systems for any earthheat loop transfer system whether used with a pipeline or not.

FIG. 4 shows a system 40 according to the present invention which has anearth loop 45 through which heat transfer fluid circulates (e.g. by apump or pumps, not shown) which is in fluid communication with atransfer fluid line 47 of a movable heat exchange tube or jacket 46 inposition on a portion of a pipeline 48 above the earth E. The tube orjacket 46 can, according to the present invention, be configured andfashioned to completely encircle a portion of a pipeline or to coveronly a part of its full circumference. Connection 49 a, 49 b on the loop45 and connections 49 c, 49 d on the line 47 make it possible todisconnect the line 47 from the loop 45 and to re-connect the line 47 toconnections 49 e, 49 f of another loop 45 a so that the line 47 is thenin fluid communication with the loop 45 a and heat transfer fluid can becirculated (e.g. with a pump or pumps, not shown) through the loop 45 aand the tube or jacket 46. It is within the scope of this invention touse any desired number of earth loops 45 and/or 45 a in the system 40;and/or to use a plurality of loops of different depths to access earthareas of different temperatures to apply heat transfer fluids at oneselected temperature to the pipeline.

FIG. 5 illustrates a system 50 with a pipeline 58 (which is either aboveground or buried in the earth). An earth loop 52 (which is eithercompletely buried in the earth and extends to a desired depth or has atleast a portion buried in the earth and extending down to a desireddepth which is at a desired temperature) is in fluid communication witha heat exchange apparatus 56, which, in one aspect, is a conduit influid communication with the loop 52. A pump 54 circulates fluid throughthe apparatus 56 and the loop 52. A pump may also be used outside thepipeline 58 to accomplish this circulation. The system 50, thus, heats(or cools) fluid flowing in the pipeline 58. Any loop disclosed hereinmay, similarly, be interconnected with an apparatus within a pipelinelike the apparatus 56.

FIG. 6 shows a system 60 with a plurality of conduits 66 a, 66 b, in apipeline 68. Each conduit 66 a, 66 b is in fluid communication with acorresponding earth loop 62 a, 62 b, part or all of which is buried inthe earth down to a desired depth (as may be the pipeline 68). Pumps 64a, 64 b, respectively circulate heat transfer fluid through theirrespective conduit/loop combinations. It is within the scope of thisinvention to provide a plurality of such conduit/loop combinations in apipeline or portion thereof.

FIG. 7 illustrates a system 70 according to the present invention whichhas a mobile heat exchange apparatus 76 movable disposed within apipeline 78. A line 77 partially within the apparatus 76 is, viaconnectors 79, in fluid communication with an earth loop 72. A pump 74(which may be located outside the pipeline) circulates heat transferfluid through the loop 72 and line 77. The apparatus 76 may be motorizedand remotely controllable so that it may be selectively positioned at adesired location in the pipeline 78. The line 77 may be of any suitablelength to allow the apparatus 76 to reach a desired point within thepipeline with respect to the connectors 79. In another aspect thepipeline is provided with a series of spaced-apart connectors 79, eachassociated with an earth loop and/or a series of spaced- apart earthloops adjacent the pipeline. A remote-controlled apparatus 76 isselectively movable to any desired set of connectors within the pipelineat which a connection is made of the line 77. The apparatus 76 thenengages in a heat exchange operation within the pipeline—either in anevacuated pipeline or in a pipeline with fluid flowing, frozen, orpartially frozen therein.

FIG. 8 illustrates a system 80 according to the present invention whichincludes an earth loop 82 a through which heat transfer fluid iscirculated by a pump 84 a. The earth loop 82 a is in fluid communicationwith a well loop 82 b which extends down into a well 81 in the earth E(which may be any type of well). Optional pumping apparatus 84 b pumpsfluid out of the well 81. Due to a temperature differential between theearth at a lower end of the loop 82 a and the interior of the well 81,the heat transfer fluid circulated through the loops 82 a and 82 b heats(or cools) the interior of the well 81 facilitating operations withinthe well 81, including, but not limited to facilitating the operation ofsystems, devices, and apparatuses within the well 81. Optionally via aconduit 82 c heat transfer fluid may be circulated to and from theapparatus 84 b. Optionally insulating material 87 and/or an insulatingenclosure may be used on any part of parts of the loop 82 a (as with anyloop disclosed herein). Also, any of the above-ground apparatus andequipment may also be insulated. Any of the heat exchange systemsdisclosed herein (e.g. but not limited to those of FIGS. 1-8) may beused to provide heat transfer fluid to a heat exchange system which thenheats or cools a pipeline, rather than to such a system that is directlyin contact with a pipeline as in FIGS. 1-8.

FIG. 9A shows a system 90 according to the present invention for anoffshore rig R above the ocean floor F. (Of course, it is within thescope of the present invention to use a system 90, or any earth conduitor loop and associated apparatuses and devices, with a land rig.) Aplurality of heat transfer loops 92 a, 92 b, 92 c (any one or two ofwhich may be deleted) are operatively connected to the rig R to supplyheat transfer fluid of different temperatures for use on the rig R. Theloops extend down below a water surface W.

The loops 92 b and 92 c extend only down into the water and do notextend into the earth E below the ocean floor. Part of the loop 92 c isinsulated with insulation 97 c so that heat transfer fluid circulatedthrough the loop 92 c is primarily exposed to the temperature of thewater near the ocean floor F. Appropriate pumps and control apparatuses(not shown) for all the loops are on the rig R. The loop 92 a is withinthe earth and is insulated with insulation 97 a both in the water anddown to a certain depth in the earth, insuring that heat transfer fluidcirculated through this loop is primarily exposed to a temperature at adesired depth in the earth. FIG. 9B shows an addition to the system 90of FIG. 9A which includes a series of heat exchange tubes 93 around aroom 91 (or apparatus) on the rig R. The tubes 93 are in fluidcommunication with the heat transfer loop 92 a so that heat exchangefluid flowing therein and through the tubes 93 may heat or cool the room91 (or apparatus). Any, some or all of the loops 92 a, 92 b, and/or 92 cmay be used for heat exchange with the room 91. The rig R may be a landrig and then all the loops 92 a, 92 b, 92 c would extend into the earth.

FIG. 10 shows a system 100 according to the present invention for a rigR2 (like the rig R) in the ocean O above an ocean floor F2. A productionriser or a tubular 101 extends down from the rig R2 to a well 103 in theearth E. An earth loop 102 is in fluid communication with a heatexchange apparatus 106 that encompasses the riser or tubular 101 so thata pump 104 can pump the heat transfer fluid through the loop 102 andthrough the apparatus 106. Optionally, a pump 104 a on the rig R2 can beused to pump the heat transfer fluid via conduits 105 a, 105 b in fluidcommunication with the apparatus 106. The apparatus 106 may be insulatedwith insulation 107.

FIG. 11 illustrates a system 110 according to the present inventionwhich includes an earth loop 112 in the earth E having a crossoverportion A at an earth depth E1 and a lowermost portion B at a differentearth depth E2. Valving apparatuses V1 initially preventing fluid flowdown to the lowermost loop portion B are activatable in response tofluid pumped at a pre-determined rate. For example, when heat transferfluid is pumped through the loop 112 (with a pump or pumps, not shown)at a rate lower than the predetermined rate, it flows through the loopportion A and is exposed to the earth's temperature at the depth E1.When fluid is pumped at or above the pre-determined rate, the valvingapparatuses V1 open and the heat transfer fluid flows through the loopportion B and is exposed to the earth's temperature at the depth E2.

FIG. 12 illustrates a system 120, like the system 110, and like numeralsand symbols indicate the same items and things; but the valvingapparatuses V1 are deleted and a single valving apparatus is used thatselectively allows flow either through the loop portion A (while closingoff flow to the loop portion B) or through the loop portion B (whileclosing off flow through the loop portion A). It is within the scope ofthis invention to provide any earth loop herein with two or morecrossovers, like the crossover portion A, and corresponding valvingapparatus so that two, three, four or more portions of an earth loop areselectively accessible, thereby making it possible to access an earthdepth at a desired temperature for heat transfer. Also, according to thepresent invention any portion of any such loop may be insulated toenhance heat transfer efficiency at a desired earth depth.

FIG. 13 discloses a system 120 a, like the system 120 (and likeidentifying letters and numerals identify like parts), with a pump P1within the loop for pumping fluid through the loop. Such a pump may bedisposed at any desired location in the loop and used with any loopdisclosed herein. Such a pump may be remotely activated via appropriatewiring extending from the pump to the surface or the pump may beactivated via a wireless system.

FIG. 14 illustrates a system 140 according to the present inventionwhich has an earth heat loop within the earth having one or more flowcontrol devices F1 and/or F2 for controlling fluid flow in the loop or apart thereof. In certain embodiments such a flow control device (ordevices) insures that heat transfer fluid moves at an optimum ratethrough a loop portion to optimize heat transfer between the fluid andthe earth. Any suitable flow control device may be used, including, butnot limited to, known restricted opening flow restrictors, andcommercially available Flosert devices from Lee Company.

Any earth loop in any system or method according to the presentinvention may be, but is not limited to, any earth heat exchange loop asdisclosed in U.S. Pat. Nos. 5,590,715; 5,758,724; 5,244,037; 5,261,251;5,671,608; 5,477,914; 5,706,888; and in Swiss Patent CH 653120A5—allsuch patents incorporated fully herein for all purposes. Althoughvarious preferred embodiments of the present invention are describedabove as using earth loops, it is within certain embodiments of thepresent invention to use an earth heat exchange system, e.g., but notlimited to, as disclosed in U.S. Pat. Nos. 4,448,237, 4,286,651;4,574,875; 4,912,941; 3,609,980; 4,325,228; 5,183,100; and 5,322,115(all such patents incorporated fully herein for all purposes) throughwhich to circulate heat transfer fluid for heat exchange with apipeline, rig, riser, etc. according to the present invention.

The present invention, therefore, provides in certain, but notnecessarily all embodiments, a method for exchanging heat between apipeline through which fluid is flowable and an earth conduit throughwhich heat transfer fluid is flowable flows, the method includingflowing heat transfer fluid through a first earth conduit extending froman earth surface down into the earth and having a first conduit portionin the earth at a desired location with a desired earth temperature;emplacing heat exchange apparatus with respect to a pipeline portion ofa pipeline, the heat exchange apparatus including a heat exchange devicefor exchanging heat with the pipeline and connection apparatus,connecting the connection apparatus in fluid communication with the heatexchange device and the first earth conduit; and flowing the heattransfer fluid through the first earth conduit and then in heat exchangerelation with the heat exchange device to transfer heat between thepipeline portion and the heat transfer fluid. Such a method may includeone, some or (in any possible combination) of the following: flowingfluid through the pipeline, and exchanging heat between fluid flowingthrough the pipeline and the heat transfer fluid; wherein the firstearth conduit is a loop with an inlet through which heat transfer fluidenters the earth conduit and an outlet from which the heat transferfluid exits the conduit; pumping the heat transfer fluid through thefirst earth conduit and through the heat exchange apparatus with pumpapparatus; powering the pump apparatus with power generated by a solarpower system; powering the pump apparatus with power generated by a windpower system; controlling the pump apparatus from a location remote fromthe pipeline; wherein the heat exchange device is on an exterior of thepipeline; wherein the heat exchange device is within the pipeline;wherein the first earth conduit is within a first earth bore extendingdown into the earth and the heat exchange device is within a wellborespaced-apart from the first earth bore, the method also includingexchanging heat between an interior of the wellbore and heat transferfluid flowing through the heat exchange device in the wellbore; whereina portion of the first earth conduit is insulated to enhance heattransfer efficiency between the heat transfer fluid and the heatexchange device; controlling rate of fluid flow within the first earthconduit with a flow rate controller within the first earth conduit;wherein the first earth conduit has at least two loop portions each influid communication with the first earth conduit for the flowtherethrough of heat transfer fluid and valve apparatus controls fluidflow to the at least two loop portions, the at least two loop portionsspaced apart from each other and at different levels at differenttemperatures in the earth, the method including selectively flowing heattransfer fluid through only one of the at least two loop portions;wherein the pipeline portion of the pipeline is underwater, aboveground, or underground; wherein the pump apparatus is underwater, aboveground or under ground; and/or the method including stopping heattransfer fluid flow, disconnecting the connection apparatus,re-connecting the connection apparatus between a second portion of thepipeline and a second earth conduit extending from an earth surface downinto the earth and having a second conduit portion in the earth at adesired location with a desired earth temperature, and flowing the heattransfer fluid through the second earth conduit to the heat exchangedevice.

The present invention, therefore, provides in certain, but notnecessarily all embodiments, a method for providing heat transfer fluidto a rig (offshore or land) involved in wellbore operations forexchanging heat between the rig (and/or apparatus or structure on therig) and a conduit extending from the rig, the conduit extending throughmaterial having at least two areas of different temperature, the methodincluding flowing heat transfer fluid through the conduit and to andthrough heat exchange apparatus on the rig, and insulating a portion ofthe conduit in at least one of the at least two areas of differenttemperature to enhance heat transfer efficiency between the heattransfer fluid and the heat exchange apparatus; wherein the rig is anoffshore rig and the material includes water adjacent the rig; whereinthe rig is an offshore rig and the material includes water adjacent therig and earth below the water; wherein the rig is an offshore rig andthe heat exchange apparatus includes a heat exchange device forexchanging heat between the heat transfer fluid and a riser extendingdown from the rig.

The present invention also discloses, in at least certain embodiments,systems for use in such methods.

FIG. 15 shows a system 200 according to the present invention which hasa header 210 which distributes or collects fluids between a plurality ofspaced terminals 11 and a centralized point or facility 14. Whileterminals 11 (only some are numbered for clarity) can be any station orstructure to which fluids are to be distributed and/or collected, theyare illustrated in FIG. 15 as wellheads of production/injection wellswhich, in turn, have been drilled and completed at spaced locations onthe earth's surface 12. As will be understood by those skilled in thisart, the spacing of the wellheads 11, as shown in FIG. 15, is forillustration purposes only is not necessarily to scale. This spacingbetween wellheads 11 in actual field applications may vary from about 8feet or less up to 120 feet or more.

As shown in FIG. 15, all of the wellheads 11 are fluidly connected to asingle manifold or header 10 by means of respective lateral pipes 13.Where the wells are producing wells, the production fluids (e.g. oil,gas, and/or water) from a particular well flow through its wellhead 11and lateral pipe 13 into header 10. The fluids commingle within theheader 10 and flow through the header to a centralized location 14 forfurther handling. Where the wells are injection wells, the reverse istrue. That is, an injection fluid (e.g. water for disposal or for use inwater-flooding operations) flows from centralized location 14, throughheader 10, and out into each of the wellheads 11 through its respectivelateral pipe 13. Of course, it should be understood that certainwellheads 11 can be shut-in when the situation dictates and fluids willbe produced or injected through only those wellheads that are open (i.e.on-line).

One of the lateral pipes 213 is shown in fluid communication with anearth heat transfer system 224 which can either cool or heat the lateralpipe 213, and/or fluid therein, depending on the earth temperatureadjacent part of a heat transfer conduit 225. The system 224 may be anyearth heat transfer system with any conduit or loop disclosed hereinwith any associated apparatuses, heat exchangers, pumps, equipmentand/or devices disclosed herein. The header 210 may be any suitableheader, including, but not limited to, a header as disclosed in U.S.Pat. No. 6,062,308 issued May 16, 2000 and incorporated fully herein forall purposes.

An earth heat transfer system 223 (like the system 224) is in directcommunication with one of the terminals or wellheads 211 and providesheating or cooling of the wellhead and/or of fluid therein. Any lateralpipe 213 (or all of them) may have a heating/cooling system 224 or thesystem 224 may be in communication with more than one lateral pipe 213.Also, any terminal or wellhead 211 may be in fluid communication with asystem 223 or the system 223 may be in communication with more than oneterminal or wellhead.

An earth heat transfer system 222 (like the system 224) is incommunication with the header 210 and provides for heating or cooling offluid flowing in the header 210 and/or of the header itself.

An earth heat transfer system 221 (like the system 224) is incommunication with the central facility 14 and can heat or cool partthereof and/or fluid therein. Alternatively, or in addition to thesefunctions, fluid flowing from the central facility 14 to the header 210may be heated or cooled by the system 221.

Optionally, any or all (but one) of the systems 221-224 may beeliminated from the system 200.

FIG. 16 shows a system 300 according to the present invention forproviding fluid at desired temperatures from one or more earth loops(any disclosed herein) to various parts, apparatuses, and/or locationsin a system for introducing bacteria and/or other microorganisms into ahydrocarbon bearing and/or oil bearing earth formation 310. It is knownin the prior art that after hydrocarbons have ben pumped from an earthwellbore, or after a well has been pumped dry, and, in some cases,flushed with steam and water to force out sluggish crude, as much astwo-thirds of the oil can remain in the formation, often stuck tounderground earth and rocks. It is known in the prior art to releaseoil-munching bacteria to promote further hydrocarbon production.

A single strain of bacteria may be used or, after mixing several strainsof bacteria, they are placed in water or other appropriate fluid,optionally along with nutrients to help them grow and/or survive, andare then pumped into oil-bearing or hydrocarbon-bearing rock. Thebacteria chew into the sticky oil masses (often blobs with theconsistency of asphalt), breaking the tangle of complex carbon moleculesinto smaller pieces. More water or other suitable fluid is then pumpedin to flush out the loosened oil. In many cases, such bacteria must becarefully bred, due to the extreme conditions often encountered in anearth well. Temperatures can rise to 140° F. or higher. Often bacteriahave to be specially raised for each location, as the type of chemicalsfound in crude varies widely. It has been estimated that bacteria coulddouble production in up to 40 percent of oil wells.

At various stages in the production of hydrocarbons illustrated in FIG.16 temperature can be critical both for effectiveness of themicroorganisms and for efficient operation of devices, equipment,methods, and apparatus.

As shown in FIG. 16 microorganisms 370, e.g. bacteria, are pumped by apump 306 in fluid 372 down an earth wellbore 320 extending from earthsurface S down into the hydrocarbon bearing formation 310. Equipment 302is for producing and/or handling the microorganisms 370 which are storedin storage device or vessel 304 (mobile or on-site) from which the pump306 pumps them in an appropriate fluid (e.g. water and nutrients) intothe wellbore 320. The prior art discloses a variety of microorganisms,methods of their production and handling, and associated apparatuses andequipment including those of U.S. Pat. Nos. 6,294,351; 5,858,766;5,885,825; 6,207,056; 5,840,182; 5,297,625; and 5,492,828—allincorporated fully herein for all purposes.

Any earth loop described herein may be used at any point in the system300 (FIG. 16) to provide energy transfer fluid at a desired temperature.Any such loop may have any part or portion insulated to facilitateprovision of earth energy transfer fluid at a desired temperature.Although FIG. 16 shows a land-based system, it is to be understood thatit is within the scope of this invention to use any such earth loop inconnection with a wellbore beneath a water surface (e.g. lake, sea,ocean). Although the earth loops shown in FIG. 16 each extend down to acertain underground level in the earth, it is to be understood that anyof these loops may extend down to any desired depth.

An earth loop 330 has portions thereof insulated with insulatingmaterial 373, 374. Energy fluid flow lines 337 and 338, connected,respectively, to associated surface apparatus (pump(s), flow line(s),conduit(s), meter(s), valve(s) and/or heat exchanger(s) etc.) 335 and336, provides energy transfer fluid either directly from the earth loop330 to the equipment 302 or this fluid works in heat exchange relationwith other fluid that then flows in the lines 337, 338 (as is true ofthe possible fluid flow programs for any earth loop in the system 300and its associated surface apparatus). The earth loop 330 can providefluid at a desired temperature for either cooling or heating theequipment 302 and/or any part or portion thereof (as is true for everyearth loop in the system 300). Via lines 339 and 340, fluid at a desiredtemperature is provided to the storage device for vessel 304. Similarly,via flow lines 341, 342 fluid at a desired temperature is provided tothe pump 306 and via flow lines 343, 344 to a flow conduit 375. It is tobe understood that any flow lines associated with any earth loop and itssurface apparatus in FIG. 16 may be used to provide heat or cooling forthe outside of a device, vessel, conduit, pipe apparatus, line, or bore,or to the interior of any such device, etc., e.g. but not limited to,such methods and systems as described herein for providing fluid at adesired temperature on, around, or within pipe, line, etc.

Apparatus 351 provides fluid 376 at a desired temperature which ispumped into the hydrocarbon bearing formation 310 through a bore 377.Via flow lines 349, 350 fluid at a desired temperature is provided tothe apparatus 351. The flow lines 349, 350 are connected to associatedsurface apparatus 347, 348, respectively, of an earth loop 332. Thefluid 376 may be at a temperature to enhance the activity ofmicroorganisms, to prolong their life, or to optimize their activity.The bore 377 may extend to any part of the earth and/or to any part ofthe formation 310. Alternatively, the fluid 376 may be used tofacilitate the flow of hydrocarbons to the bore 322.

Fluid at a desired temperature is provided to a surface system 352 inlines 353, 356 related to associated surface apparatus 354, 355respectively of an earth loop 333. The surface system 352 may be part ofthe pumping apparatus 324; or it may be separate therefrom and include,e.g. collection and/or storage apparatus for microorganisms pumped up inthe bore 322.

Via flow lines 359 and 360 fluid at a desired temperature is provided toheat exchange apparatus 357 around the wellbore 322. The lines 359, 360are related to surface apparatus 363, 364, respectively, associated withan earth loop 334. Fluid at a desired temperature is provided to a heatexchange apparatus 358 within the wellbore 322 via flow lines 361, 362which, respectively, are related to the surface apparatus 364, 363.

FIGS. 17A-17C illustrate the application of teachings of the presentinvention to subject matter of U.S. Pat. No. 6,212,890 which isincorporated fully herein for all purposes. Various parts, items,equipment, lines, conduits, etc. of the systems of U.S. Pat. No.6,212,890 are heated or cooled, or use heat or cooling. Any earth loopor loops according to the present invention (any disclosed herein) maybe used in the systems.

Power plant 410, FIG. 17A, comprises source 412A of geothermal steam (inone aspect low pressure), and turbo-generator 414 which includes turbine416 (in one aspect low pressure) coupled to generator 418. Source 412Aincludes separator 413A that receives geothermal fluid from well 411Aand separates the fluid into a vapor stream, and a liquid stream. Thevapor stream that exits into conduit 420 constitutes the geothermalsteam, and the liquid stream that exits into conduit 421 is constitutedby brine. Conduit 420 connected to source 412 applies the geothermalsteam to the turbine wherein expansion of the steam takes place drivinggenerator 418 which produces electricity, and producing expanded steamin exhaust line 419. Condenser 422 connected to exhaust line 419receives expanded steam exhausted from turbine 416 and condenses thesteam producing condensate in drain line 424. Condenser 422 includessteam heat exchanger 426 for receiving the expanded steam, and fan 428for cooling steam present in steam heat exchanger 426. In one aspect,compressor 434 is connected to steam heat exchanger 426 for the purposeof removing non-condensable gases from the steam heat exchanger, andpressurizing the gases for environmentally safe disposal, preferably ina re-injection well (not shown). In one embodiment, conduit 420 carriessteam from source 412A to the input of steam turbine 416, therebyconstituting means for applying steam from the source to the turbine.Expansion of the steam takes place in the turbine driving generator 418which produces electricity, and expanded steam is produced that isapplied to heat exchanger 426 within which are located a plurality offinned tubes 427 into which the expanded steam flows (although it iswithin the scope of this invention to use any suitable heat exchanger inany embodiment of FIGS. 17A-17C). The finned tubes are cooled withambient air by operation of fan 429 which induces ambient air to flowover them. The removal of non-condensable gases from the condenser alsocontributes to the effectiveness of the condenser. In one aspect, thetubes 427 are of stainless steel to preclude or reduce damage by contactwith the expanded geothermal steam.

Dashed lines from surface apparatus 411I of an earth loop system 411Hindicate the provision of heat from heat exchange transfer fluidtraversing the earth loop to a line 411G to the separator 413A (oralternatively to the separator itself), to the conduit 420, and/or tothe turbine 416. Such heat may be applied on, in or within the line 411Gand conduit 420 and it is to be understood that each dashed lineculminates in appropriate heat exchange apparatus and/or heat transferapparatus, including, but not limited to, any such apparatus disclosedfor any embodiment of the present invention.

Dotted lines from surface apparatus 411K of an earth loop system 411Jindicate the provision of cooling fluid from heat exchange transferfluid traversing the earth loop to: a line compressor 434; to the line419; to the generator 418; to the condenser 422; to the line 424; and/orto the heat exchanger 426. Such cooling fluid may be applied on, in orwithin these items and it is to be understood that each dotted lineculminates in appropriate heat exchange apparatus and/or heat transferapparatus, including, but not limited to, any such apparatus disclosedfor any embodiment of the present invention.

The earth loop system 411H and the earth loop system 411J each has anearth loop extending down to a desired depth for accessing a desiredunderground temperature for heating or cooling.

Steam condensate can be disposed of by re-injecting it or used for otherpurposes, e.g. make-up water for neighboring cooling towers, irrigation,drinking water, etc. Furthermore, the extracted non-condensable gasescan be released to the atmosphere or re-injected into a re-injectionwell, or first chemically treated before being disposed of.

In some fields, production wells produce higher pressure geothermalfluid. Typically, a well that produces geothermal fluid which, afterseparation into brine and steam that have a temperature in the range ofabout 131-160.degree. C., is referred to as an intermediate pressurewell. A well that produces geothermal fluid at a higher pressure, i.e.above about 160.degree. C., is referred to as a high pressure well. Thepresent invention is also applicable to both types of wells. A powerplant 440 shown in FIG. 17B and a power plant 460 shown in FIG. 17C usegeothermal fluid at any desired pressure. In one aspect, the fluid forthe power plant 440 is at an intermediate pressure produced byproduction well 411B; and the fluid for the power plant 460 is at a highpressure produced by production well 411C. Instead of the wells shown inFIGS. 17A-17C, any source of geothermal fluid may be used.

The power plant 440 comprises source 412B (which may be, but is notlimited to) a source of low pressure geothermal steam, andturbo-generator 414 which includes steam turbine 416 coupled togenerator 418. Conduit 420 supplies the steam to turbine 416 wherein thesteam is expanded driving the attached generator and producing exhauststeam in conduit 419 that is condensed in condenser 422 as describedabove. In this embodiment of the invention, like reference numeralsdesignate like components in the other embodiments. Source 412B includesseparator 413B, turbo-generator 441 that includes primary steam turbine442 coupled to generator 443, and primary heat exchanger 444. Separator413B receives geothermal fluid from well 411B and separates the fluidinto two streams, one containing steam (e.g., but not limited to at atemperature of between 131.degree. C. to 160.degree. C.) that exits intoconduit 446, and the other containing brine that exits into conduit 448.Conduit 446 applies geothermal steam from separator 413B to the primarysteam turbine (which, in one aspect, is an intermediate pressure steamturbine) wherein expansion of the steam takes place driving generator443 which produces electricity, and producing primary expanded steam inexhaust line 445. Primary heat exchanger 444 receives the primaryexhaust steam via conduit 445, and brine via conduit 448, reheating theprimary exhaust steam and producing geothermal steam (which in oneaspect is low pressure) that exits via conduit 420. In power plant 40,which utilizes geothermal steam produced by the separator, primary heatexchanger 444 is constituted by indirect contact reheater 446 having aheat transfer surface 447 that divides the heat exchanger into sides 449and 450. Side 449 receives brine from the separator; and side 450receives primary expanded steam exhausted from the primary turbine. Heatin the brine is transferred through surface 447 to the primary exhauststeam thus reheating the steam which exits via conduit 420 (and, in oneaspect, constitutes low pressure geothermal steam described above). Thisgeothermal steam is applied to turbine 416 of turbo-generator 414 whoseoperation is the same as that described above. In one embodiment of theinvention, non-condensable gases are preferably removed from side 450 ofreheater 446 to enhance the heat transfer characteristics of thereheater.

Dashed lines from surface apparatus 411M of an earth loop system 411Lindicate the provision of heat from heat exchange transfer fluidtraversing the earth loop to a line from the well 411B to the separator413B (or alternatively to the separator itself), to the conduit 446, tothe turbine 442, and/or to the turbine 416. Such heat may be applied on,in or within these items and it is to be understood that each dashedline culminates in appropriate heat exchange apparatus and/or heattransfer apparatus, including, but not limited to, any such apparatusdisclosed for any embodiment of the present invention.

Dotted lines from surface apparatus 411R of an earth loop system 411Pindicate the provision of cooling fluid from heat exchange transferfluid traversing the earth loop to: a heat exchanger 444; a conduit 445;a generator 443; a line 419; a generator 418; and items 422, 424, 426,427, and 428 as described above. Such cooling fluid may be applied on,in or within these items and it is to be understood that each dottedline culminates in appropriate heat exchange apparatus and/or heattransfer apparatus, including, but not limited to, any such apparatusdisclosed for any embodiment of the present invention.

The earth loop system 411L and the earth loop system 411P each has anearth loop extending down to a desired depth for accessing a desiredunderground temperature for heating or cooling.

The power plant 460 includes a source 412C of geothermal steam, andturbo-generator 414 which includes steam turbine 416 coupled togenerator 418. Conduit 420 supplies the steam to turbine 416 wherein thesteam is expanded driving the attached generator and producing exhauststeam in conduit 419 that is condensed in condenser 422 as describedabove. In this embodiment of the invention, like reference numeralsdesignate like components in the other embodiments. Source 412C includesseparator 413C, turbo-generator 461 that includes primary steam turbine462 coupled to generator 463, and primary heat exchanger 464. Separator413C receives geothermal fluid (which in one aspect is high pressure)from well 411C and separates the fluid into two streams, one containingsteam (e.g., at a temperature of above 160.degree. C.) that exits intoconduit 466, and the other containing brine that exits into conduit 468.Conduit 466 applies geothermal steam (which in one aspect is highpressure) from separator 413C to the primary steam turbine (which, inone aspect, is a high pressure steam turbine) wherein expansion of thesteam takes place driving generator 463 which produces electricity, andproducing primary expanded steam in exhaust line 465. Primary heatexchanger 464 receives brine via conduit 468, and produces geothermalsteam (e.g., in one aspect low pressure) that exits the primary heatexchanger and is combined with primary exhaust steam in conduit 465 toproduce low pressure geothermal steam in conduit 420. In power plant 60,which utilizes geothermal steam produced by the separator, primary heatexchanger 464 is constituted by flash chamber 469 for receiving brinefrom conduit 468 and producing flashed steam at a temperature higherthan the temperature of the primary expanded steam in conduit 465. Theflashed steam exits chamber 465 in conduit 467 and is combined at 469with the primary expanded steam. The combination constitutes geothermalsteam (in one aspect low pressure) in conduit 420 described above. Thisgeothermal steam is applied to turbine 416 (in one aspect a low pressureturbine) of turbo-generator 414 whose operation is the same as thatdescribed above. In one embodiment of the invention, non-condensablegases are preferably removed from chamber 469 to enhance the heattransfer characteristics of condenser 422.

Dashed lines from surface apparatus 411T of an earth loop system 411Sindicate the provision of heat from heat exchange transfer fluidtraversing the earth loop to a conduit 467; to a conduit 465; and/or toa conduit 420. Such heat may be applied on, in or within these items andit is to be understood that each dashed line culminates in appropriateheat exchange apparatus and/or heat transfer apparatus, including, butnot limited to, any such apparatus disclosed for any embodiment of thepresent invention. Any of the earth loop systems of FIGS. 17A and 17Bmay be used in the system of FIG. 17C. It is also to be understood that,according to the present invention, the earth loop in any of the earthloop systems of FIGS. 17A-17C may be any earth loop(s) described hereinaccording to the present invention and that any item, conduit, line,apparatus, or part of any of the systems 410, 440, and 460 may be heatedor cooled as desired with heat transfer fluid from such an earth loop.

In certain particular embodiments, the steam turbine 414 may be a steamcondensing turbine, while the steam turbine 441 and the steam turbine461 are back pressure steam turbines.

In certain aspects, the present invention discloses improvements to theprocesses disclosed in U.S. Pat. No. 6,543,535 issued on Apr. 8, 2003which is incorporated fully herein for all purposes. In certainembodiments processes according to the present invention include aprocess for stimulating the activity of microbial consortia in ahydrocarbon-bearing, subterranean formation to convert hydrocarbons tomethane and other hydrocarbon gases which can be produced, the processutilizing an earth loop heat exchange system to maintain microorganismsat desired temperatures. The hydrocarbons can be carbonaceous depositsin solid, liquid, or gaseous form such as coal, oil shale, tar sands,oil formations, and rich gas or the hydrocarbons can be unwantedsubsurface hydrocarbons of a hydrocarbon reclamation project. Ananalysis is made of the environmental conditions in the formation,preferably by obtaining samples of formation fluid and/or rock and thenanalyzing the samples. The presence of microbial consortia in theformation is determined, preferably by analyzing one formation samplesfor the presence of microorganisms in the samples. Optionally, acharacterization, preferably a genetic characterization, is made of atleast one microorganism of the consortia, at least one of which is amethanogenic microorganism, and comparing said characterization with atleast one known characterization, preferably a genetic characterization,derived from a known microorganism having one or more known ecologicalcharacteristics. This information, together with the informationobtained from the analysis of the fluid and rock, is used to determinean ecological environment that promotes in situ microbial degradation offormation hydrocarbons and/or promotes microbial generation of methaneby at least one methanogenic microorganism of the consortia. Thisecological information is then used as the basis for modifying theformation environment to stimulate microorganism activity and/or sustainmicrobial conversion of formation hydrocarbons to methane. The formationenvironment can be modified by carrying out at least one of thefollowing stimulation techniques: (1) adding, subtracting, and/ormaintaining components needed for microbial growth, and/or (2)controlling and/or maintaining formation environmental factors such aschemistry, temperature, salinity, and pressure. Recovery of methaneproduced by the microbial activity can be by any suitable gas productiontechnology.

The following example illustrates a specific procedure for practicingone embodiment of the invention. For this hypothetical example,reference is made to FIG. 18 which illustrates a system 500 according tothe present invention with a conventional injection well 520 andproduction well 521 penetrating a hydrocarbon-bearing formation 522 thatcontains indigenous microorganisms. The hydrocarbon-bearing formation522 contains a water and residual oil zone 523 and a mobile oil zone524. Water (indicated by arrows 525) containing one or more stimulantsselected in accordance with the teachings of U.S. Pat. No. 6,543,535 areinjected through the injection well 520 into the formation 522. Thewater containing one or more stimulants enhances or stimulates microbialactivity in the pores containing oil to convert at least part of the oilto methane. As the subsurface microbes increase the conversion of oil inpores in the formation to methane, the methane concentration (not shown)increases in the fluid phases (water and oil). Eventually the methaneconcentration may exceed the saturation level in the fluids and formbubbles of methane 535. The generated methane 535 can migrate to the topof the formation 522 to form a separate gas zone 526 which can flow tothe production well 521, or flow as dissolved gas in fluid produced atthe production well 521. The methane 535 can for example be dissolved inoil in the mobile oil zone 524 or dissolved in produced water. Themethane can also flow as a separate gas phase along with produced oiland water. The methane is recovered at a production well 521 along withproduced oil and water.

As shown in a FIG. 18 an apparatus 351 (as described above, FIG. 16),provides fluid 376 at a desired temperature (e.g. a temperature (e.g. atemperature to help sustain microorganism life or to enhancemicroorganism microbial activity) that is pumped (pump not shown; can bepart of apparatus 351 or exterior thereto) into the formation 522through a conduit or bore 377. Heat transfer fluid (or, in one aspectthe fluid 376) flows in an earth loop 332 between associated surfaceapparatuses 347 and 348. Via flow lines 349, 350 this fluid flows toapparatus 351 from which it is introduced into the formation 522. Theconduit or bore 377 may extend to any part of the formation 522.Alternatively, the fluid 376 may be used to facilitate the flow ofhydrocarbons up into the bore 377 and, in one such aspect, fluid 376 ispumped intermittently into the formation 322 (e.g. with a separate pump,not shown, or with pumping apparatus included in the apparatus 351).

Optionally, the apparatus 351 includes heat exchange apparatus 351 a andoptional aqueous solution (or fluid) supply apparatus 351 b . Fluidflows from line 349, to the heat exchange apparatus 351 a, to the line350, and back to the earth loop and aqueous fluid, supplied by theaqueous solution supply apparatus, 351 b flows to the heat exchangeapparatus 351 a and then from it into the conduit or bore 377, the fluid376 having undergone heat transfer with the heat transfer fluid (e.g.,but not limited to, at a final temperature of less than 125° C., 100°C., or 100° F., corresponding to a similar temperature of the heattransfer fluid flowing from the earth loop 332).

As desired, any portion or all of the earth loop 332 may be insulated(e.g. as described above) so that a desired aqueous solution temperatureis achieved (or, in aspects in which the fluid pumped into the formationis the fluid that flows through the earth loop, so that a desiredtemperature for this fluid is achieved). The earth loop 332 may be anydesired length extending to any desired depth (corresponding to aformation depth at a desired temperature for heat transfer, to include,if desired, both cooling or heating of heat transfer fluid) and/or anyearth loop or loops disclosed herein may be used. Optionally, a heattransfer fluid supply apparatus 332 a provides a continuous and/oron-demand supply of heat transfer fluid to the line 349 or, in oneaspect, a continuous and/or on-demand supply of aqueous solution as thefluid 376.

Any desired number of earth loops 332 may be used in the system 500(with the other apparatuses, lines, etc. as described above)spaced-apart in the formation 522. Also, it is within the scope of thepresent invention to provide heat transfer with an earth loop system asdescribed herein for the injection well 520 and/or the production well521, either around the walls' exterior circumference or within the wallsat any point or points thereof.

The present invention, therefore, in at least certain aspects, providesprocesses for stimulating the activity of microbial consortia in ahydrocarbon-bearing including the acts of: (a) analyzing one or morecomponents of the formation to determine characteristics of theformation environment; (b) detecting the presence of microbial consortiawithin the formation; (c) determining one or more characterizations ofone or more microorganisms of the consortia; (d) using informationobtained from acts (a) and (c) for determining an ecological environmentthat promotes in situ microbial degradation of hydrocarbons by at leastone microorganism of the consortia; and (e) modifying the formationenvironment based on the determinations of act (d) to stimulatemicrobial degradation of hydrocarbons, wherein modifying the formationenvironment comprises injecting into the formation an aqueous solutionthat modifies formation temperature, the aqueous solution processed inheat exchange relation with an earth loop heat exchange system. Such aprocess may include one or some (in any possible combination) of thefollowing: wherein the earth loop heat exchange system has an earth loopextending from an earth surface down into the formation with heattransfer fluid flowing through the earth loop and heat transferapparatus for transferring heat between the aqueous solution and theheat transfer fluid; wherein at least a portion of the earth loop isinsulated; wherein solution supply apparatus is in fluid communicationwith the earth loop heat exchange system for supplying aqueous solutionthereto so that a desired flow of aqueous solution is provided to theformation; wherein the earth loop heat exchange system has an earth loopextending from an earth surface down into the formation and the aqueoussolution is flowed through the earth loop prior to injecting the aqueoussolution into the formation; wherein solution supply apparatus is influid communication with the earth loop heat exchange system forsupplying aqueous solution thereto so that a desired flow of aqueoussolution is provided to the formation; wherein temperature of theaqueous solution following processing in heat exchange relation with theearth loop heat exchange system is less than 100 degrees or 125 degreesCentigrade; providing with a primary system a fluid with additionalmicroorganisms, the primary system including introduction apparatus,with the introduction apparatus introducing the fluid with additionalmicroorganisms into the formation, the microorganisms for facilitatingremoval of the hyrdrocarbons from the formation, effecting heat exchangebetween the fluid with additional microorganisms and heat transfer fluidthat has traversed an earth loop of the earth loop heat exchange system,the earth loop heat exchange system with an earth loop extending from anearth surface down into the formation with heat transfer fluid flowingthrough the earth loop and heat transfer apparatus for transferring heatbetween the fluid with the additional microorganisms and the heattransfer fluid; and/or with removing apparatus, removing hydrocarbonsfrom the formation bearing said hydrocarbons.

The present invention, therefore, in at least certain aspects, providesprocesses for stimulating the activity of microbial consortia in ahydrocarbon-bearing, subterranean formation to convert the hydrocarbonsto methane, including the acts of: (a) analyzing one or more componentsof the formation to determine characteristics of the formationenvironment; (b) detecting the presence of microbial consortia withinthe formation; (c) determining one or more characterizations of one ormore microorganisms of the consortia, at least one of thecharacterizations being of at least one methanogenic microorganism, andcomparing the one or more characterizations with at least one knowncharacterization derived from at least one known microorganism havingone or more known physiological and ecological characteristics; (d)using information obtained from acts (a) and (c) for determining anecological environment that promotes in situ microbial degradation ofhydrocarbons and promotes microbial generation of methane by at leastone methanogenic microorganism of the consortia; and (e) modifying theformation environment based on the determinations of act (d) tostimulate microbial conversion of hydrocarbons to methane, whereinmodifying the formation environment includes injecting into theformation an aqueous solution that modifies formation temperature, theaqueous solution provided by an earth loop heat exchange system. Such aprocess may include one or some (in any possible combination) of thefollowing: with removing apparatus, removing hydrocarbons from theformation bearing said hydrocarbons; wherein effecting said heatexchange between fluid with microorganisms and heat transfer fluidprolongs life of said microorganisms; wherein effecting heat exchangebetween fluid with microorganisms and heat transfer fluid enhancesactivity of microorganisms for facilitating removal of saidhydrocarbons; wherein the microorganisms are bacteria; and/or whereinthe hydrocarbons are oil.

In conclusion, therefore, it is seen that the present invention and theembodiments disclosed herein and those covered by the appended claimsare well adapted to carry out the objectives and obtain the ends setforth. Certain changes can be made in the subject matter withoutdeparting from the spirit and the scope of this invention. It isrealized that changes are possible within the scope of this inventionand it is further intended that each element or step recited in any ofthe following claims is to be understood as referring to all equivalentelements or steps. The following claims are intended to cover theinvention as broadly as legally possible in whatever form it may beutilized. The invention claimed herein is new and novel in accordancewith 35 U.S.C. § 102 and satisfies the conditions for patentability in §102. The invention claimed herein is not obvious in accordance with 35U.S.C. § 103 and satisfies the conditions for patentability in § 103.The inventors may rely on the Doctrine of Equivalents to determine andassess the scope of their invention and of the claims that follow asthey may pertain to apparatus not materially departing from, but outsideof, the literal scope of the invention as set forth in the followingclaims.

1. An earth loop heat transfer system comprising a heat transfer loopextending from an earth surface down into the earth, the heat transferloop having a first portion extending down into the earth and a secondportion, the heat transfer loop having a bottom portion at a first levelin the earth, the first level at a first temperature, heat transferfluid flowable down to the bottom portion in the first portion of theheat transfer loop and up therefrom into the second portion of the heattransfer loop, heat transfer fluid then flowable up in the secondportion of the heat transfer loop to the earth surface, heattransferring at the bottom portion between the earth at the firsttemperature, the heat transfer fluid flowing through the bottom portion,and valve apparatus in the heat transfer loop for controlling flow ofheat transfer fluid in the heat transfer loop apparatus.
 2. The earthloop heat transfer system of claim 1 further comprising pump apparatusfor pumping heat transfer fluid in the heat transfer loop.
 3. The earthloop heat transfer system of claim 1 further comprising a crossoverportion with a first end and a second end, the first end in fluidcommunication with the first portion of the heat transfer loop and thesecond end in fluid communication with the second portion of the heattransfer loop, the crossover portion above the bottom portion, thecrossover portion at a second level above the first level, the secondlevel at a second temperature different from the first temperature, andheat transfer fluid flowable down to the crossover portion in the firstportion of the heat transfer loop and then therethrough into the secondportion of the heat transfer loop without flowing to the bottom portionfor flow up to the earth surface, heat transferring at the crossoverportion between earth at the second temperature and the heat transferfluid.
 4. The earth loop heat transfer system of claim 3 furthercomprising the valve apparatus located at a junction of the firstportion of the heat transfer loop and the crossover portion forselectively flowing heat transfer fluid through the crossover portion orthrough the bottom portion.
 5. The earth loop heat transfer system ofclaim 3 further comprising the valve apparatus including a first valveand a second valve, the first valve in the first portion of the heattransfer loop, the second valve in the second portion of the heattransfer loop, and the first valve and the second valve selectivelyoperable to permit heat transfer fluid flow through the bottom portionor to prevent heat transfer fluid flow through the bottom portion. 6.The earth loop heat transfer system of claim 1 further comprising atleast one flow control device in the heat transfer loop.
 7. The earthloop heat transfer system of claim 6 wherein the at least one flowcontrol device is two spaced-apart flow control devices.
 8. The earthloop heat transfer system of claim 6 wherein the at least one flowcontrol device is a restricted opening flow restrictor.
 9. The earthloop heat transfer system of claim 1 further comprising insulation on atleast a portion of the heat transfer loop.
 10. The earth loop heattransfer system of claim 1 wherein the valve apparatus is activatable inresponse to fluid pumped at a pre-determined rate.
 11. An earth loopheat transfer system comprising a heat transfer loop extending from anearth surface down into the earth, the heat transfer loop having a firstportion extending down into the earth and a second portion, the heattransfer loop having a bottom portion at a first level in the earth, thefirst level at a first temperature, heat transfer fluid flowable down tothe bottom portion in the first portion of the heat transfer loop and uptherefrom into the second portion of the heat transfer loop, heattransfer fluid then flowable up in the second portion of the heattransfer loop to the earth surface, heat transferring at the bottomportion between the earth at the first temperature, the heat transferfluid flowing through the bottom portion, valve apparatus in the heattransfer loop for controlling flow of heat transfer fluid in the heattransfer loop apparatus, a crossover portion with a first end and asecond end, the first end in fluid communication with the first portionof the heat transfer loop and the second end in fluid communication withthe second portion of the heat transfer loop, the crossover portionabove the bottom portion, the crossover portion at a second level abovethe first level, the second level at a second temperature different fromthe first temperature, heat transfer fluid flowable down to thecrossover portion in the first portion of the heat transfer loop andthen therethrough into the second portion of the heat transfer loopwithout flowing to the bottom portion for flow up to the earth surface,heat transferring at the crossover portion between earth at the secondtemperature and the heat transfer fluid, and insulation on at least aportion of the heat transfer loop.
 12. A method for transferring heatbetween the earth and a heat transfer fluid, the method comprisingflowing heat transfer fluid into an earth loop heat transfer system, theearth loop heat transfer system comprising a heat transfer loopextending from an earth surface down into the earth, the heat transferloop having a first portion extending down into the earth and a secondportion, the heat transfer loop having a bottom portion at a first levelin the earth, the first level at a first temperature, heat transferfluid flowable down to the bottom portion in the first portion of theheat transfer loop and up therefrom into the second portion of the heattransfer loop, heat transfer fluid then flowable up in the secondportion of the heat transfer loop to the earth surface, heattransferring at the bottom portion between the earth at the firsttemperature, the heat transfer fluid flowing through the bottom portion,and valve apparatus in the heat transfer loop for controlling flow ofheat transfer fluid in the heat transfer loop apparatus, flowing theheat transfer fluid to and through the bottom portion of the heattransfer loop, and transferring heat at the bottom portion between theearth and the heat transfer fluid at the first temperature.
 13. Themethod of claim 12 wherein the earth loop heat transfer system includespump apparatus for pumping heat transfer fluid in the heat transferloop, the method further comprising pumping the heat transfer fluid inthe heat transfer loop.
 14. The method of claim 12 wherein the earthloop heat transfer system includes a crossover portion with a first endand a second end, the first end in fluid communication with the firstportion of the heat transfer loop and the second end in fluidcommunication with the second portion of the heat transfer loop, thecrossover portion above the bottom portion, the crossover portion at asecond level above the first level, the second level at a secondtemperature different from the first temperature, and heat transferfluid flowable down to the crossover portion in the first portion of theheat transfer loop and then therethrough into the second portion of theheat transfer loop without flowing to the bottom portion for flow up tothe earth surface, heat transferring at the crossover portion betweenearth at the second temperature and the heat transfer fluid, the methodfurther comprising flowing heat transfer fluid through the crossoverportion to effect heat transfer from the earth to the heat transferfluid at the second temperature.
 15. The method of claim 14 wherein theearth loop heat transfer system includes the valve apparatus located ata junction of the first portion of the heat transfer loop and thecrossover portion for selectively flowing heat transfer fluid throughthe crossover portion or through the bottom portion, the method furthercomprising selectively flowing the heat transfer fluid through thecrossover portion.
 16. The method of claim 14 wherein the earth loopheat transfer system includes the valve apparatus located at a junctionof the first portion of the heat transfer loop and the crossover portionfor selectively flowing heat transfer fluid through the crossoverportion or through the bottom portion, the method further comprisingselectively flowing the heat transfer fluid through the bottom portion.17. The method of claim 12 wherein the earth loop heat transfer systemincludes the valve apparatus activatable in response to fluid pumped ata pre-determined rate, the method further comprising activating thevalve apparatus in response to fluid pumped therethrough at apre-determined rate.
 18. The method of claim 12 wherein the earth loopheat transfer system includes at least one flow control device in theheat transfer loop, wherein the at least one flow control device is arestricted opening flow restrictor, the method further comprisingrestricting flow of the heat transfer fluid through the heat transferloop.
 19. The method of claim 12 wherein at least a portion of the heattransfer loop is insulated.
 20. The method of claim 12 wherein in theearth loop heat transfer system the valve apparatus includes a firstvalve and a second valve, the first valve in the first portion of theheat transfer loop, the second valve in the second portion of the heattransfer loop, and the first valve and the second valve selectivelyoperable to permit heat transfer fluid flow through the bottom portionor to prevent heat transfer fluid flow through the bottom portion, themethod further comprising selectively flowing heat transfer fluidthrough the bottom portion.